DEFECT LEVELS IN SILICON BOMBARDED WITH LIGHT-IONS

Defect levels produced by H+, D+ and He+ ion bombardment of silicon wi th different phosphorus doping and oxygen content have been investigat ed using deep-level transient spectroscopy. After He+ implantation onl y pure damage defect levels occur, whereas after H+ and D+ implantatio n additional hydrogen-related defects are observed. Defect profiles ar e generally much broader than theoretical distributions. For vacancy-r elated defect levels both the peak concentration and the halfwidth of the profiles depend only on the Fermi energy. The broadening which inc reases with decreasing doping level is explained by a model based on e lectric-field-enhanced diffusion of the vacancies out of the collision cascades. For the most prominent hydrogen-related defect, E(c)-0.30 e V, a mechanism for its formation has been deduced. This defect is tent atively identified as (H-V) pair.